1. Field of the Invention
The present invention relates to an optical disk apparatus for detecting direction of a relative movement between a laser beam of an optical head used in an optical device, which records data to an optical disk and reproduces data from the optical disk.
2. Description of the Related Art
In an image filing system, an optical disk apparatus is used. In the optical disk apparatus, data is recorded on a track or recorded data is regenerated while an optical disk in which a groove and a land (recording track) are spirally or concentrically formed is rotating. In the land of the optical disk, there is provided a header portion having a pre-pit, which is formatted in advance, and a pit continuous to the head portion is formed, thereby recording data.
As the above-mentioned apparatus, there is conventionally proposed an apparatus for detecting a moving direction to the optical disk of the optical head (see Japanese Patent Application KOKAI Publication No. 5-89485).
More specifically, in an optical disk apparatus in which the optical head is moved in a radial direction of the optical disk, light from the optical disk is detected along the movement of the optical head, thereby obtaining a track error signal (push-pull signal) and a track addition signal, a groove detection pulse is output in response to the track addition signal, a track detection pulse is output in response to the track error signal so that the moving direction of the optical head is detected in response to the groove detection pulse and the track detection pulse.
However, according to the above-mentioned detecting apparatus, when a signal with a low reflection rate serving as a preformat signal, and a signal with a high reflection rate, serving as a recording data signal, are provided on the optical disk, and a portion having no groove (discontinuous groove portion) is formed in the preformat portion, it is difficult to remove these signals from the track addition signal and output a correct groove detection signal, and an erroneous direction signal is output.
In other words, there is a possibility that the moving direction of the optical disk of the optical head will be erroneously detected by an influence of pits other than the groove on the optical disk and concave-convex portions.
As mentioned above, there is conventionally the problem in which the moving direction of the optical disk of the optical head cannot be correctly detected.